This invention relates to gas-liquid separators for use in engine cooling systems for deaerating the coolant fluid. More particularly, this invention relates to a gas-liquid separator for separating gas from the coolant fluid by means of centrifugal action.
Internal combustion engines, such as diesel engines, are typically fluid cooled by means of a water coolant which is circulated through the engine by a coolant system. Frequently, the air from combustion gases are entrained in the coolant fluid which detracts from the cooling capability of the fluid. This causes undesired heating of the engine and components thereof.
To solve this problem, various types of engines coolant deaeration systems have been evolved. For example, U.S. Pat. Nos. 3,246,637 and 3,255,740, both to Walsh, show systems of this type. In addition, certain coolant systems employ an open radiator top tank in which coolant delivered to the top of the radiator core is contained in an open cavity that also contains a reverse volume of coolant as well as an air space. Bubbles in the fluid coolant are separated in this cavity by means of baffling.
However, with the advent of diesel engines having higher horsepowers and consequently increased coolant flows, the open top tank becomes a source of air entrainment due to the turbulence caused by the delivery of large quantities of coolant. This type of solution has not been entirely satisfactory in eliminating the problem of entrained gas in coolant fluid.
Accordingly, new solutions have been proposed. One is to entirely redesign engines to keep out combuston gases. Another is to design radiator top or expansion tanks to be more effective. However, these approaches require quite severe modifications to existing engine systems and are therefore undesirable from the standpoint of cost. A better approach has been proposed which requires merely the addition of a simple device to existing cooling systems. Such a device is a flow separator which may be inserted to a coolant fluid conduit to enable separation of gas bubbles from the coolant fluid by means of centrifugal action. Such flow separators comprise a body having an inlet and an outlet, which inlet and outlet are positioned at approximately a 90.degree. angle to each other. Typicallly, the coolant fluid having entrained air enters the inlet and is directed around a curved internal wall of the flow separator body whereupon air bubbles are directed to the center of curvature of the wall by means of centrifugal action. A withdrawal tube or conduit is placed at the center of curvature for withdrawing air bubbles to, for example, a radiator top tank. The deaerated coolant fluid then passes out through the outlet.
One problem with the flow separator thus described is that the unit is difficult to adapt to existing engine systems, since coolant conduits are typically in straight lines and do not ordinarily accommodate 90.degree. bends required by the described separator. The 90.degree. bend also requires a substantial change in coolant direction which is inefficient from the standpoint of friction flow losses.